1. Field of the Invention
This invention relates generally to flexible hose couplings. More particularly, it relates to quick connect hose couplings, and specifically to push-to-connect and quick to disconnect flexible hose couplings.
2. Description of the Prior Art
Quick connect couplings are known. In such couplings a port adapter may include the female portion or port and be pre-assembled on an associated fixture, machine or equipment or the female portion or port may be machined as part of associated fixtures, machinery or equipment. The hose connection or male portion or hose stem, including a hose insert portion and a ferrule, is typically attached to an open end of the hose to be connected to the fixture, machinery or equipment. The hose stem portion has a hose insert portion, which is inserted into the open end of the hose. A ferrule, or the like, is then typically compressed about the hose end containing the insert causing all portions to be permanently affixed. Merely pressing the hose connection portion into the female portion or port subsequently completes the hose connection. Such quick connect couplings are particularly desirable when the hose must be connected in a location which is not readily accessible since it eliminates the need for starting threads and the danger of cross threading and eliminates the need to use a related tool which might not fit in the available space. Since the port adapter may be threaded into place as a pre-assembly operation, or the port preexists in the associated fixture, machine or equipment, it is easy to insure that the port is proper and ready. Further, the time of assembly and, in turn, the assembly costs are reduced.
Historically, the considerations that have driven the design of such couplings have included complexity of port design, effecting machineability, complexity of stem design, complexity and location of sealing elements such as o-rings or other shape of seals, complexity and location of locking components such as clips of various shapes, total number of components needed to complete the coupling, and interplay of the geometry of the port and the stem. All of these have greatly affected the cost of producing such couplings which impacts greatly upon their economic viability.
It has also been important to ensure that such couplings can be used safely and reliably. Obviously, one of the primary purposes of such couplings is to provide a long lasting leak-free connection. However, over time, increasing emphasis has been placed upon safety. Typical quick disconnect characteristic of such couplings give rise to a greater opportunity for inadvertent and sudden disconnects, with grave results. This is particularly true in the environments where use of such couplings is especially appealing. These include industrial or heavy machinery locations where installations of fluid connections are numerous, dense, and almost inaccessible, having movement of many hard and heavy objects nearby, including the fixtures upon which the couplings are often attached. Unexpected impacts upon quick to disconnect couplings or maintenance in such difficult quarters can increase the likelihood of inadvertent disconnects. Inadvertent disconnects on pressurized systems can lead to damaged or broken machines, destroyed premises, severe injuries to maintenance or other workers, or even death, such as through unexpected machinery movement or spray of very hot fluids at high pressure.
One example of a push to connect and quick to disconnect coupling can be found in U.S. Pat. No. 3,773,360 to Timbers, which is incorporated herein by this reference. Timbers appears to be an attempt to provide both straight-forward push to connect and quick to disconnect processes while simplifying port and stem design to contain cost. Timbers discloses the advantage of a simple port design where no sealing or locking components or clips are integral. However, the disclosed stem is more complex including all sealing and locking components. Further, the locking component is intricate and relatively complex. Significantly, the disclosed coupling requires an additional component, or stop member, to make the coupling resistant to inadvertent disconnection. The complexity and additional components increases the cost of the coupling. The coupling of Timbers completes its fluid connection by simply pressing the male portion into the female portion. With the stop member removed, the coupling is disconnected by additional insertion of the male portion into the female portion into closer engagement. This causes the port to compress the locking component. The intricate shape of the locking component then allows it to grab onto the stem and stay compressed such that its locking function is deactivated. The two portions are then separated.
It was apparently contemplated that the coupling of Timbers would be inadvertently disconnected too easily to be safe in many environments. Accordingly, the stop member was included on the disclosed fitting. The stop member interferes with the male and female portions being pressed into closer engagement by filling space between the female and male portions. It would appear that the coupling with the stop member in place is resistant to inadvertent disconnection.
However, both the use and shape of the stop member leaves substantial opportunity for the coupling to experience disastrous inadvertent disconnection. First, there is no way to ensure that the stop member will be properly installed on the coupling during the entire time of its deployment. The stop member could be absent from the beginning or removed at any time during the life of the coupling leaving no tell-tale sign that anything is amiss. In such a condition the coupling would no longer be resistant to inadvertent disconnection. Second, the disclosed shape of the stop member includes a loop that extends radially away from the coupling. In the environments described above as those where the use of a quick to connect and quick to disconnect coupling is especially appealing, the loop would be subject to gathering debris or being hooked by moving objects. This gives rise to substantial opportunity for the stop member to be stripped from the coupling. Once again, the coupling would no longer be resistant to inadvertent disconnection.
Safety is also compromised by the existence of such a rigid loop in many industrial or heavy machinery environments. It can be a direct source of damage or injury through the entanglement of debris, tools, clothing, hair or fingers. Further, it is not inconsequential that every time the coupling is to be disconnected, the metal loop, comprising the stop member, is removed to become lost as hazardous debris.
Additional problems arise in solutions, such as Timbers and other prior art quick to connect and disconnect couplings employing a clip. There is the potential for the clip to reciprocate in its annular groove or the like. This reciprocation may occur along the centerline axis of the coupling or stem during operation in which impulsing pressure and/or lateral loading is present. This reciprocating motion or “shuttling” effect is not desirable as it may accelerate wear on the retention elements of the male and female fitting portions. This may consequently have an adverse effect on the potential life of the connection. This shuttling effect may become more apparent and significant on larger bore couplings in which the clip cross-sectional thickness and consequently its annular groove width is greater, allowing more room for the shuttling to occur.